The secret levels weren't that hard. 40 and 30 were far tougher. I expected rage, and got incepted gimmick levels. I thought you'd go for what S3 did, but with multiple platforms.
Clunky controls. I don't like the attitude. Freerunning feels unsatisfying when you know you aren't really in it unless you have a shell with you. Bad soundtrack.
After passing the 3 million get, I went to the shop to buy all the guns I passed and 48 nukes. Midway through the nuke mash, I hit the clear data button about five times. 4/5, might recommend.