I got more than my moneys worth from this game. But an update with an in-app purchase for a paid game? Something about the principle of the whole thing seems wrong.
I would have been less upset if Origin8 was more forthcoming that we have a 27MB update, but it really is only 2 levels free, after that it is an in app purchase to get the rest rather than:
The Campaign 2 expansion pack DLC is now available on Android! It contains a 15 level campaign across 15 brand new maps (all of which can be unlocked for Endless mode), new weapons, enemies and landscape features, plus a new Commander Mech specialising in ranged offence.
Maybe next time just put the new updates in a separate game using the same engine and call it Sentinel 4?