I finally found some gameplay footage and this looks nothing like previous games in the series

@darkvare: they said on the bomb/beast cast a couple times that it wasnt like the previous games. Its more like a character crossover thing.

Travis Strikes Again is a spin-off of the No More Heroes series, not a mainline sequel. Suda has said that if TSA sells well, he's hoping to make NMH 3.

TSA is composed of six sub-games that take inspiration from retro games and indie games. The gameplay video above shows off only one of the six games. The other five will feature different kinds of gameplay. It should be no wonder that TSA's gameplay is quite different from that in NMH 1 & 2.

Edit: Correction: there are technically seven sub-games, but the seventh one is a secret. In a recent interview Suda described the sub-games like this:

[Travis] will be going into the worlds of different games in the game’s universe. The first one he’ll be going into, which is what has been unveiled in the [video above], is ‘Electronic Thunder Tiger II,’ which is a sequel to an arcade game in that universe. The second game ‘Killer Marathon,’ which is a pinball game. The third game is ‘Life is Destroyed,’ which is a simulation puzzle game. The fourth game is ‘Coffee and Donuts,’ which is an action adventure game. The fifth game is ‘Golden Dragon GP,’ which is a racing game. The sixth game is ‘Serious Moonlight,’ which is a huge, triple-A RPG. And the last one is a secret.