Twelve bills are expected to be passed before Parliament is dissolved
Labour and the Conservatives have "colluded" to water down plans for constitutional reform in a rush to get bills passed, the Lib Dems have said.
Thursday was the last day Parliament could sit before the election and saw a frantic rush to get bills passed, known as the "wash-up".
Ministers made concessions on a number of key policies, saying it was necessary to ensure bills get passed.
But many MPs were upset at the compromises that have been agreed.
There had been angry exchanges in the Commons on Wednesday as MPs debated proposals in the digital economy bill to cut off the internet connections of persistent copyright infringers.
Many said they were not being given enough time to consider far-reaching proposals to tackle this but the Commons backed the bill, which was later approved by the Lords.
Peers also spent their few remaining hours of debating time considering what aspects of the government's Constitutional Governance and Renewal Bill could be salvaged.
Parliament was prorogued - or adjourned - on Thursday evening, prior to its official dissolution on Monday.
The Lib Dems said the two main parties had been in cahoots to dilute proposed reform of the House of Lords.
Measures permitting peers to resign or be expelled and the repeal of restrictions on demonstrations outside Parliament were dropped, in addition to commitments to hold a referendum on the voting system and to phase out the remaining hereditary peers.
"The process of 'wash-up' is now washed up", David Howarth, the party's justice spokesman, said.
"The way in which the two front benches of the larger parties colluded and then got it wrong and ended up with this disaster is something they need to reflect on."
Ministers say the entire bill - which still includes measures for anyone sitting in Parliament to pay tax on all their earnings and implementing recommendations on expenses reforms - would have been jeopardised if no agreement had been reached.
Shadow justice secretary Dominic Grieve said there was "no collusion" between the two parties and he had merely been asked what the opposition was prepared to accept to back individual bills.
Among measures to be dropped in the 12 government bills considered in the wash-up were new education guarantees for pupils and parents, the mandatory teaching of sex education and a 10% duty hike on cider.
The Conservatives also agreed to drop their opposition to the DNA of people not charged with any offence being kept on a national database for six years, but said they would repeal this if they won power.
A number of private members' bills - put forward by individual MPs - will also become law after getting Parliamentary approval.
These include a ban on under-18s using tanning salons and a clampdown on so-called "vulture funds" suing some of the world's poorest countries for debts.