One time I was playing the game and reached level 15 (2nd level while playing as an alien) I beat the sentinel, but died as at the time my last shot hit the sentinel, the missile was about to hit the alien when the script of the sentinel's crash landing was loaded. The missile hit the alien as I didn't manage to put the shield on and thus I had to fight against the very same sentinel. However, when I beat the sentinel for the second time, there was no cutscene of the sentinel's crash landing as its script had already been loaded the first time I had beaten it. It makes me wonder whether such a script is possible to be skipped without dying.

Update to this thread: I've just discovered how that script can be skipped. The last word would be more correct if I put it with quotation marks. The thing is that when the player destroys the sentinel for the first time, the script will be loaded. By "the first time" I mean the first time from opening the game. That means that if the player destroys the sentinel from level 15, then any other attempt on beating level 15 will not load the very same script after destroying the sentinel. That'd require beating level 15 before the run, thus setting up would be necessary. As that'd provide an unfair advantage in the run where an attempt has to be made by beating levels from 1 to 17, I'd opt for rejecting any run that doesn't present the sentinel's crash landing in level 15. Level 16 also presents a script at the beginning where the mech comes in. To skip it one would have to play level 16 before the run. Therefore, I'd also opt for rejecting any run that doesn't present the level 16 script as well. The only set-up that I myself would allow would be the colour choice. In the paid version the player can choose whatever the colour they want. In the free version the option is to either pay for a game, watch an ad or change the colour in level 17 with those "colour switch chambers."