It is difficult to protect the original ideas that go into making your new computer game, online booking platform, or other computer program, as only the source code behind a computer program is protected by copyright, and generally a game etc. can be very closely copied by a competitor without any access to the source code. They will write new code which has the same end result as the code of the program being copied.
However, it is not impossible to protect the ideas behind your computer programs. Copyright kicks in for compilations, e.g. GUIs, where the various elements have been put together with skill and effort. Designs of screen displays and icons, and other visible elements of computer programs, are capable of registration as EU Registered Designs which can give you a monopoly in them for up to 25 years. In some cases the inventive ideas behind features of computer programs can be protected by patent - think of Apple’s slide-to-unlock feature – and, in the US, computer programs can be patented.
So it is not entirely impossible to protect the novel ideas behind a computer program, but certainly difficult.