Note: work in progress.
Okay, so according to the frame data, Tandem Engine is +19 on block and +23 on hit. Now, what the hell does that mean? This move is fairly weird, and I personally think it will eventually become a very powerful tool. I’ve done some testing so you guys don’t have to.
Introduction stuff, feel free to skip:Tandem Engine has 3 parts, just like every other move: Startup, active frames, and recovery. LP Tandem Engine has 21 frames startup, which is a lot, and it gets worse from there. It also has a large number of active frames, which is when your opponent gets sucked in. However, the general consensus is that Tandem Engine goes immediately into its recovery frames once your opponent is right next to Seth. Your opponent is left blocking/open for a variable amount of time depending on how far away they were when they get sucked in.
Now that we’ve established how Tandem Engine works, I’ll explain how safe/unsafe/advantageous it is to use Tandem Engine. In case you don’t know, the range of Tandem Engine depends on which punch you use. LP goes about half the screen, MP about two thirds, and HP goes almost the entire screen. The different versions seem to suck the opponent in at the same speeds, and the maximum distance you can move the opponent when blocking is about two and a half training room squares (this means that you should always use the weakest version possible because the startup is faster). If the opponent isn’t next to you by then, you go into your recovery. However, if the opponent isn’t blocking Tandem Engine, they are sucked in much more quickly, which will usually leave you with enough frame advantage generally to combo with s.hp or cr.lp. If the opponent was close, you have enough time to combo into s.hk or cr.hp. However, there is a range where you can’t combo off of Tandem Engine on hit.
Anyway, I figured out that Tandem Engine is -4 on block if it isn’t cancelled out of. If Guile is sucked in from across the screen, he can punish you with Flash Kick, which is a 4-frame move. Cammy, on the other hand, cannot punish with Cannon Spike, which is a 5 frame move. On hit, Tandem Engine seems to be completely unpunishable, but it doesn’t seem to give you any frame advantage. I think Seth is -1 or even on hit, but I haven’t tested with Zangief’s ultra yet.
The frame data seems to be describing what happens when the opponent is right next to you. For example, you can combo into a level 1 Focus Attack if you use Tandem Engine at point blank, which is a 21 frame move. If LP Tandem has 69 total frames, then the recovery should be 69 - 21 - 24 = 24 frames. That means that since Tandem is +23 on hit and +19 on block, the total hitstun/blockstun is 47 frames and 43 frames respectively.
21 frame startup, 23 frame advantage on hit~