The shops are full of Israeli food and clothes but most people here can barely afford them. Construction projects — sewage treatment plants, schools — are getting started but far fewer than needed. The border with Egypt, once sealed, is open but few people cross because security clearance is hard to get. And rockets and mortar shells fly daily from here into Israel, as Israeli troops carry out brief raids.

Two years after the Israeli military swooped down here in a three-week war that destroyed thousands of buildings, killed about 1,300 people and largely deterred rocket fire, things are starting to shift again in Gaza. But they seem to be shifting backward, creating a sense of déjà vu. The economic siege is easing, and the border is heating up. Israel hoped that the blockade would break Hamas. Instead, Hamas is fully in charge, Israel is frustrated and another confrontation seems possible.

“Everyone in the Israeli government knows this situation cannot go on forever,” said a top Israeli official, insisting on anonymity because of the delicacy of the topic. “It is an illusion to think that there can ever be peace here with Hamas in power.”

Just as such talk is common in the Israeli security establishment, so here in Gaza official talk of resistance and rejection is standard.

“I would rather die a martyr like my son than shake the hand of my enemy,” Yusef Mansi, the Hamas minister of public works and housing, said in an interview devoted mostly to rebuilding after the war. He was responding to a question about reconciliation with Israel.

Since September, when Israel and the Palestinian Authority started peace talks, there have been 20 to 30 rockets and mortar shells shot monthly into Israel, double the rate for the first part of the year. Although most seem to be the work of groups other than Hamas, Israel argues that Hamas is in charge and will be held responsible.

“In the last two months there has been a shift, which means that from now on unless we start doing something different, the deterrence will go down,” an Israeli military commander said in an interview under military rules of anonymity. “Hamas has gained a lot of military capabilities in the last two years.”

Whether or not the mutual hostility will produce another war, there is, at the same time, a mild shift in daily life for the 1.5 million people living in this coastal strip. It involves a slow rebuilding of a kind of Gaza normality — always a painful normality since two thirds of the inhabitants are refugees and 80 percent depend on foreign aid.

The change started over the summer after a Turkish flotilla tried to break the Israeli siege by sailing to Gaza. Israeli commandos, meeting violent resistance aboard one of the ships, killed nine men. International outrage followed and the Israeli authorities acknowledged that their policy of keeping Gaza on economic subsistence was neither ending Hamas’s rule nor helping Israel’s declining international image. A change was ordered.

Maj. Gen. Eitan Dangot, who runs civilian affairs in Gaza for the Israeli Defense Ministry, said that 78 civilian projects had been approved and that they included hospitals, schools and housing, although only half had been started. All those projects involve international groups that decline to work with Hamas.

After an Israeli cabinet decision this month calling for Gaza to be permitted to export more goods, he spoke at a joint briefing for foreign journalists with Yuli Edelstein, the minister for public diplomacy. Mr. Edelstein declared, “The government is doing all in its power to ease the life of the residents of the Gaza Strip.”

Most here would disagree. There is little doubt that compared with a year or two ago, many more consumer goods, and a wider variety, are being allowed in from Israel. The number of daily truckloads is expected to reach 400 in the coming months, four times what it was two years ago. But Gazans still cannot cross into Israel. And the economy remains idle. A private sector that once employed 125,000 has barely 10,000 workers.

“Our stomachs are full but our pockets are still empty,” noted Nasser el-Helo, a Gaza businessman who cannot carry out much business.

Twenty-two human rights and aid organizations recently published a report saying that Israel had not yet carried out its obligations to change its policy and that life here remained unchanged. Construction, the greatest need after the war, is the slowest effort to get started because Israel fears that cement, gravel and steel, if permitted in unsupervised, would be diverted to Hamas’s military.

This means that businesses like the one belonging to Mohammad Abu Marzouk, which used to employ 1,500 construction workers, have nothing to do. Mr. Abu Marzouk, who built the six-story Gaza parliament — completing it two months before Israel leveled it in the war — said he now had five employees.

“We watch the clouds,” he said of their days.

Tony Blair, the former British prime minister who serves as the international envoy to Palestinian institutions, said that an important way to counter Hamas’s supremacy was to support an alternative power base in the private sector, which tended toward a Western orientation.

But the risks there are real. Ibrahim Abrach, who teaches political science at Al Azhar University here and opposes Hamas, said the easing of the Israeli siege was strengthening Hamas.

“I fear that further lifting of the siege will lead to the loss of the West Bank,” he said in an interview, referring to the fact that the Fatah-dominated Palestinian Authority, a rival of Hamas, runs the West Bank. “It is very hard to lift the siege and not boost Hamas.”

He favors doing so as part of reconciliation with Fatah. So far, that too has proved elusive, although the biggest project in Gaza is a $50 million sewage treatment system officially overseen by the Palestinian Authority. The Israelis hope that such projects will give Gazans faith in the Palestinian Authority rather than in Hamas, which was elected in 2006 but violently expelled its rivals in 2007 after uneasy power-sharing efforts.

Professor Abrach said that in recent months, as conditions here had eased, Hamas had grown bolder in its suppression of dissent. His apartment has been broken into and his computer taken, he said, and he has been called into the internal security office twice. Passports of Fatah activists have been confiscated.

Khalil al-Muzayen, a filmmaker, said a Swiss-financed drama he shot about the early days of the Israeli occupation here in the 1970s was banned because it depicted Israeli solders as not all monstrous. One or two were nice.

“This was seen as pro-normalization,” he said. “But it was based on my experience.”

As he spoke, the street outside grew agitated. Hamas activists were driving and honking, practicing for the ceremony marking their 23rd anniversary as a movement. A week later, when it was held, 200,000 people attended.

Fares Akram contributed reporting.