The day 1 Crysis 2 patch has fixed a lot of bugs and gameplay issues. One of gameplay fixes was the removal of auto-aim from the PC version. Below is a list of the full patch notes:

Crysis 2 Day 1 Patch Notes

• Remove Auto Aim - Due to overwhelming community feedback, auto-aim has been removed
• Console re-enabled
• Cheat detection
• Server Browser shows correct pings
• Fixed USB headset issues
• Matches now always initiate
• Faster text chat
• Fixed hologram icon staying on screen after being used