Listen to but never believe players. Completely ignore developer folk wisdom, especially about game design.
Since we're all bringing up engines, I just want to whip out my big hateboner for how much Clickteam sucks my spider balls.
(This is the killer one) Extremely hard to make multiple levels unless you copy and paste code (that doesn't update when you change any other instances).
Integer numbers only.
The programming system is very confused on whether an object refers to a single specific instance or every instance of that object.
There's actually a logic to this stuff, but it's a fucking mess and none of it is communicated to the user. It's absolutely 100% not worth the effort to learn the ins and outs of Clickteam's garbage software when you could be devoting that to literally anything else--I have nothing against making shit in high-level game engines; I think the path of least resistance to getting your ideas working is a valid approach, it's just that Clickteam software specifically is a fucking trap and they know it.
- Global objects with their own event sheets let you avoid copypasting code (but global objects themselves are fucking broken in ways that require more arcane knowledge to avoid, like never saving or quickrunning the project with the event sheet open lest the globals in different frames desync from one another).
- Float arithmetic is possible, but you need to have constants with a decimal place in the formula or it'll default to integer logic. That means sometimes literally needing to stick "*1.0" or something on the end if the expression didn't need a constant. At least it doesn't still calculate with fucking Polish logic or whatever the fuck Klik n Play used to have.
- Object referencing is scoped by either the event triggers or certain actions like creating an object. The event order also matters, but it is consistent. It is also fucking stupid and the only way to know how to set up an event is from experience or trial-and-error, however.
The reason this is all so retarded despite Clickteam being around for so long is because they're running a scam and do not give a shit. "Clickteam Fusion" is just a reskin of Multimedia Fusion, which is a reskin of The Games Factory, which as far as I know is an update of something called Click & Create.
The only difference between them is minor shit like modern video support and a few new blending effects, and integration of community extension functionality (they just pay off the devs, and have hired one or two of them over the years as their gimps to do the actual integration work--one of whom got so sick of their shit he launched his own competitor product, although unfortunately he adopted a Clickteam-style greedy business model himself so it can't really be recommended either).
Did I mention they consider each "version 2" of these to be a new product? MMF 2.0 (new blending effects and loops that used to be an extension, no other real changes) was released as a full product too. For like three hundred bucks or something, existing owners get fucked.
Clickteam Fusion 2.5 update? Paid DLC. And I think it's like a thousand bucks total if you want the full package. Never mind that it's a pile of barely-functioning dogshit that absolutely isn't easier than just regular coding with a sprite framework.
I mean it is that too, but that's why I hate them.