There seems to be far too many games that are no different other than theme.
Half the browser based game owners i see on this site, don't seem to know how to code PHP to save their life only how to edit scripts of an engine (this does not make you a programmer in any shape of form)...i just don't understand the mentality of many game owners wanting to own a game NOW NOW NOW instead of learning how to code. Every game i try to make (albeit only 2 i made public) was from a blank php script and i find it easier to make a game from scratch than learning a game engine. Given PHP evolves and improves, an engine is soon out dated and inefficient.
I can bet 99% of PHP browser based game owners don't have a clue how to make a PHP game from scratch, and if you do, then why didn't you do it ? Ask your self this, can you do the following things without a pre-made engine:
These are very fundamental PHP game functions that cover most things that would be using arrays, functions, classes, if statements and loops.
Then there is MYSQL, do you know without even looking how to join two tables on a commonly shared id, and what do you do if two fields from both tables have the same name and you need to get one of them in the SELECT, do you know the difference between a left join and an inner join ? Is it more efficient to do a count(field) as total for a boolean check or a mysql_num_rows() function call. If you do not know even one of these things i mention you no where near ready to make/run a game. Yet time and time again people fork out cash on servers upload an engine fiddle with the settings, change the name and CSS and W00 im a game owner and im a programmer. JUST STOP!
Patience is how you get there, too many jump straight into running a game before learning this stuff. If you ever wanted to evolve to learn OOP programming, well you just won't get there if you do it this way. (Assuming you ever want to make graphical games and not browser based).
I've been embarking on my first graphical game, its taken me 2 years, but I'm learning browser technology that is still being tested, there is very little documentation, its hard as hell, but thats how you learn to master these things. I could dissect an engine and learn one (if there was one) but that does not assume its the right way to go about making the engine, there could be better ways and it depends on what you need for you're game.