supertux2: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On CentOS possible default full paths are:

/usr/bin/supertux2 - from package: supertux

You may install the required package with command yum install {package}

Error in other languages:
supertux2: bevel nie gevind nie
supertux2: comandă negăsită
supertux2: comando não encontrado
supertux2: commande introuvable
supertux2: command not found
supertux2: käsku ei ole
supertux2: không tìm thấy lệnh
supertux2: komanda nerasta
supertux2: Kommando nicht gefunden.
supertux2: kommandot finns inte
supertux2: komut yok
supertux2: nie znaleziono polecenia
supertux2: níor aimsíodh an t-ordú
supertux2: no se encontró la orden
supertux2: no s'ha trobat l'ordre
supertux2: opdracht niet gevonden
supertux2: parancs nem található
supertux2: perintah tidak ditemukan
supertux2: príkaz nenájdený
supertux2: příkaz nenalezen
supertux2: команда не найдена
supertux2: командата не е открита
supertux2: 命令找不到
supertux2: コマンドが見つかりません