Of course, the lack of a developed scripting system (and don't get me started on integrating events and Python)
just want to take a moment to double disagree.
I made a stable multithousand line/event scripted thingy animator at one point, prior to alot of rojo's recent python tweaks and fixes. like all construct you have to learn the particulars of using it, but the scripting is very powerful. the second reason for disagreeing is scripting is actually not needed in construct to make almost any game. it's when you want to do something weird like drag and drop images onto your game or something, and there isn't a plugin for it yet.
as to the original post:
if you search for anything made by quazi, tokinsom, davioware, konjak, pyteo, zotged, arsonide, saint11, or mary jane for some of the more polished stuff. also, arima's rpg, if you can hunt down vids of that, to see more polished stuff. in that list you'll find a few different genres ranging from rpg, to infinite world space sim, to 3d thumbfighting, to shmup, to topdown survival horror.
i think the previous answers were correct though. construct is very very young. it's been around for 4 years someone said? id say most active users haven't been here since the beginning, so factor the time it takes for them to get comfortable enough to tackle a large project, then either the time to tackle it alone, or build a team. so I think we're right around target :)
also, I know a few of the aforementioned folks have been working on that killer game for a long time now. but definitely don't take it as construct being unable to handle it. the ide itself definitely has some kinks and quirks to work out, but it's superpowerful and flexible. I would say most 2d games out could have been created with construct, with the exception of vector graphics based games, assuming the user(s) had the time, and artists.
edit:
ot-so-great support with data structures (whaddaya mean, you have to set array elements in the Event Sheet
I believe there's a visual array editor someone made at one point. also not sure the limitations of the competitors in this area to be honest. but, you can use python for c-like data structures, and/or the s plugin