No problem :)
Yeah, it does take a bit of getting used to - there are 3 main answers to your "built-in features" question:
1- This CE version (Clark Edition) is a project fork to improve the old/outdated project so the basis was already set by someone else.
2- Clark realised it would be better to make a new game-engine (EZGB), with way more features - but it's not finished yet (he wants to fix all EFPSE bugs first). https://cg8516.itch.io/ezgb
3- The nature of games is so diverse that not everything can be a built-in feature - scripting allows for creativity by adding your own non-standard features as required (eg: leaning/sprinting/weapon-cool downs/dialogues/fetch quests/ladders/elevators/power-ups/load-outs/skill-trees/swimming in water/floating in space/shrinking like ant-man/swinging from ropes/gravity guns/portals/teleports/enemy knock back/blood-spatters/mini-games/save-points/weapon upgrades/point-n-click puzzles/video sequences/camera shakes etc.
The original ethos being: restriction breeds creativity.
If it's too complicated for you at the moment though, you can join the discord servers (linked in the download page), I'm sure people will be happy to write/add scripts/features for you - some good people there who like a challenge if you feed them your ideas. I'd say almost anything is possible with this engine.
There is also a (much) simpler way of displaying a text message when you interact with a decoration/enemy..
Create a text.txt document and rename it as .script (file extension) with exactly the same filename as the decoration/enemy (eg: bluedoor.script).
Now in that bluedoor.script file (open it as a text file) just add the line :
text You need the blue key to open this door!
..when you run the game and click (press 'E') on the decoration/enemy, it will display the message. (I think this will work with enemies and decorations - I just don't think it will work for doors).