TTG has explicitly claimed that BttFtG is aimed at a casual gamer audience, and BttF fans, not really hard core adventure fans. And I'm fine with that; if that's the goal, the game doesn't need to be hard. Guide players, give them hints, be friendly, and make it an experience worth clicking through. Easy gameplay can be fun even to experienced players as long as it's designed well.
If the goal is to make it "simple" and "accessible", seeing how there are a lot of bugs and glitches getting in the way of that which are also quite easy to reproduce accidentally, such as the missing spray can, and not to mention some ridiculous interface designs (e.g. the full-screen inventory that can't even display all items at once for easier access), it's easy to conclude that not much thought went into making this accessible, or the thought went in the wrong direction.
Seeing how I, as an experienced adventure gamer, was stumped by some bugs, such as the invisible spray can, or that part in the guitar duel (There's a chance that Leech does the very same jump that you need to do to make him lose, but if he does it, nothing happens, so had I not planned to do the jump anyway and expected this to be a bug, I'd have concluded that jumping won't finish him off.), I don't know how that fits with the whole "adventure games for casual players" and "accessibility" philosophy.
Also the complete lack of hotspots in some scenes made me think that the game got stuck in a cutscene, examples being the one where you need to press the panic button, and the part where you need to click on the window to open it when you're kissing Jennifer.
TTG, you have great voice actors, great animators (except for the guy who made Marty's walk), one of the greatest VG composers, great references, the BttF spirit and whatnot, and the story has a lot of potential too. When looking at all those things one can see that you really like doing this.
However, I'd like to see the same love and energy flowing into designing a user friendly interface, ironing out bugs and really trying to get casual gamers into (adventure) games by producing a good example of what it feels like to play a game.